This invention relates to a method for preparing contoured honeycomb panels having good insulative and strength properties for use in thin wall construction such as aircraft and other vehicle doors and wall panels.
In the construction of aircraft bodies, refrigerated vehicles, cargo containers and the like it is frequently desirable to have a strong, lightweight, thin panel member which possesses a low thermal conductivity. In addition, for the aircraft manufacturing applications a thin contoured shape frequently is essential to fit the panel into its intended location. A thin panel structure is also necessary so that the door or other unit in which the panel is to be utilized occupies a minimum of otherwise usable space in the aircraft.
Heretofore such construction panels, as are described above, have been formed by utilizing a metal honeycomb core bounded by face sheets attached directly to the opposed end edges of the honeycomb cells. This configuration results in a high heat conductivity due to metal to metal contact at the face sheetcore interface. Insulation on the outside of the panel so formed has been found necessary to obtain the desired resistance to heat conduction necessary for aircraft usage. The resulting structure has a relatively thick cross-section due to the configuration necessary to obtain sufficient strength coupled with the thickness of the insulation material attached to the outer surfaces of the panel. In certain applications the thickness of the panel, for example, when used as a door in an aircraft has resulted in the loss of usable cargo or passenger space. Substitution of plastic or other insulative material for the metal core results in a composite having lower strength.